At Cape Cod Community College in West Barnstable, Mass., a 200 kW fuel cell provides electrical power and heat for the college's library. The fuel cell also performs an educational function; it's part of the school's environmental technology curriculum.

The fuel cell-a device that offers clean, reliable power and which has been proven in the U.S. space program-may finally be coming of age as increasing numbers of the devices are installed in real-world applications, not just demonstration projects or laboratories.

One reason for the growing interest is the need for ultra-reliable power for data applications. While fuel cells were once thought too expensive, their cost may now be justified by the economic consequences of power interruptions in critical applications. Just a few years ago, there was no need-and hence no market-for such mission-critical power.

Today, however, the bulk of all corporate information resides on mainframe computers and large servers. While major computer makers claim their servers are reliable and available 99.999 percent of the time, most on-site power conditioning and generating equipment only reaches 99 percent operating availability. Since each "9" is an order of magnitude, the electric power system is 100 to 1,000 times more likely to fail than the computers themselves, according to Sure Power Corp. of Danbury, Conn., a company that uses fuel-cell technology to deliver on-site computer-grade electricity.

Businesses lose millions

Unless this gap is closed, business stands to lose billions due to electricity problems. Business Week magazine says that in 1991 losses due to computer failures were over $26 billion-and 70 percent of those failures were due to power problems.

With these kinds of numbers, the price of fuel-cell technology suddenly becomes much more attractive.

The fuel cell is unique in that it reverses the paradigm of assured or premium power by supplying continuous power to a designated load with backup power supplied by the local utility grid.

Just what is a fuel cell? It's a piece of equipment that converts the chemical energy of a fuel directly into usable energy-electricity and heat-without combustion or rotating machinery (see sidebar). The equipment is generally contained in an unremarkable box with fuel connections-usually natural gas-and exhaust provisions.

A major difference between fuel cells is the type of electrolyte used. For stationary power generation, the three major types are phosphoric acid, carbonate, and solid oxide. While there are other differences, it is the type of electrolyte used that give the fuel cells their name.

Mature technology

The phosphoric acid approach is the most mature of the technologies. Platinum is required as a catalyst, and the converting (or reforming) of natural gas into a hydrogen-rich gas that the system needs takes place outside the fuel stacks. The system is fairly complex, with capital costs higher and efficiencies lower than those projected for the other two methods.

The carbonate fuel cell, for example, uses less expensive nickel-based electrodes, and reforming can occur inside the fuel cell stacks. Fuel cells configured to accommodate internal reforming are called direct fuel cells and are more efficient than external reforming fuel cells.

The source of hydrogen is another variable. Hydrogen can be used directly, of course, but is commonly derived from another source. Usually, the source is a fuel cell system which includes a "fuel reformer" that can extract the hydrogen from any hydrocarbon fuel-from natural gas to methanol, and even gasoline. Fuel cells today are even running on methane gas from landfills and wastewater treatment plants.

In fact, the reforming or gas processing stage is just as important as the basic fuel cell concept, since fuel cells require a relatively pure stream of hydrogen to operate properly. To supply this gas stream, ONSI Corp. engineers have developed advanced systems such as:

• fuel processing that converts a wide range of fuels into hydrogen gas streams.

• a shift converter that converts carbon monoxide into additional hydrogen.

• sulfur removal systems that remove sulfur from gas whether it is in trace quantities or hundreds of parts per million.

• halide removal systems that remove trace halide concentrations from a gas stream.

ONSI Corp, South Windsor, Conn., currently dominates the market for commercial fuel cells with over 170 units installed worldwide and a cumulative operating experience of over 2,800,000 hours as of this writing.

How much do fuel cells cost?

Like most new technology, as more units are installed and new players join the market, prices are likely to fall.

One company commercially offers fuel cell power plants for about $3,000 per kilowatt. At that price, the units are competitive in high value, "niche" markets, and in areas where electricity prices are high and natural gas prices low. A study by Arthur D. Little, Inc., predicted that when fuel cell costs drop below $1,500 per kilowatt, they will achieve market penetration nationwide.

By way of history, the U.S. Department of Energy (DOE) has funded the development of fuel cells since the 1970s, with the initial focus on phosphoric acid fuel cells (PAFC). Fuel cells utilizing that technology are now in the initial stages of commercialization. According to DOE's Federal Energy Technology Center (FETC), fuel cells have numerous advantages:

• Environmentally, fuel cells produce lower emissions than equivalent power plants. Emissions of SOx and NOx are 0.003 and 0.0004 pounds/megawatt-hour respectively. In addition, the fuel cell is quiet at 60 decibels from 100 feet. Plus, they are water self-sufficient, since fuel cell exhaust is primarily water and CO2.

• Efficiency is another selling point, ranging from 40 to 60 percent-higher when by-product heat is utilized.

• Distributed generation capability of fuel cells reduces transmission and distribution problems, as well as cost. Presently, according to DOE, between 8 and 10 percent of generated electrical power is lost between the generating station and the end-user.

• Permitting and licensing schedules are short. Natural gas fuel cell power plants have been exempt from many of California's stiff environmental regulations.

• Modular design allows the fuel cell power plant to be configured in a wide range of outputs-from a nominal 0.025 MW to greater than 50 mW.

• Fuel flexibility is another plus. The primary fuel source is hydrogen, which can be obtained from natural gas, coal-gas, methanol, landfill gas, and other fuels containing hydrocarbons.

• Cogeneration is an option that makes fuel cells attractive. High-quality heat is available for other applications.

Not just for computers

Fuel cells can be applied in a variety of applications. Cape Cod Community College in West Barnstable, Mass., as part of a $3.7 million energy savings performance contract, has installed a 200 kW fuel cell that by itself is expected to save the college about $54,000 per year in energy costs. In addition to the electrical power produced, the fuel cell heats and cools the college's library.

The college expects to realize a 20-year payback on the fuel cell, says Robert Kleghorn, facilities management director. He notes that the payback might be as short as three to five years for an installation with large water-heating needs, such as a swimming pool or a residential campus.

Nevertheless, he is pleased with the fuel cell. "It costs me $56 to produce $99 of electricity," he says. Plus, the fuel cell will provide all of the campus's electrical needs for three months out of the year.

"This is very clean power; dips and spikes just don't happen," adds Kleghorn. "It's dampened out our power system."

But the fuel cell doesn't just provide power for the campus. "We're working it into our environmental technology curriculum," says Kleghorn.

Other measures

In addition to the fuel cell, various other energy-saving measures figure into the project designed and engineered by NORESCO, an energy services company based in Framingham, Mass. Other upgrades that are expected to contribute to an annual savings of nearly $190,000 are lighting upgrades, cooking equipment conversions to natural gas, HVAC upgrades and conversion to gas from electric, and an upgraded energy-management system.

Another application where fuel cells are attractive is sites where extending or replacing power lines would be costly. For example, a hybrid fuel cell/photovoltaic power system was installed in Golden Gate National Recreational Area in California's Marin County. An existing power line would have cost $160,000 to replace, while the fuel cell, photovoltaic systems, and battery storage cost only $47,000-a savings of $113,000. The development project was funded by the National Park Service with technical assistance from National Renewable Energy Laboratory's Federal Energy Management Program (FEMP).

Other locations where fuel cells have been applied are as diverse as the New York Police Department's Central Park precinct; South County Hospital in Wakefield, R.I., a major credit-card processing center in Omaha, Neb. (see sidebar), and the Rancho Las Virgenes Biosolids Composting facility in California.

As these examples show, fuel cells are rarely installed merely as stand-alone devices. They are integrated, sometimes in creative ways, into existing systems or with other new technology to provide energy efficiency and reliability. Their growing acceptance furthers the idea that power is not just something that comes from a single source. Rather, it's part of an interdependent network where each part complements the other.

How Fuel Cells Work

Fuel cells often are described as continuously operating batteries or electrochemical engines. They make electricity by combining hydrogen ions, drawn from a hydrogen-containing fuel, with oxygen ions. While batteries contain the fuel and oxidizer internally, fuel cells utilize a supply of these key ingredients from outside the system and produce power continuously so long as the fuel supply is maintained.

The fuel cell uses these ingredients to create chemical reactions that produce either hydrogen- or oxygen-bearing ions at one of the cell's two electrodes. These ions then pass through an electrolyte, such as phosphoric acid or carbonate, and react with oxygen atoms. The result is an electric current at both electrodes, plus heat and water vapor as exhaust products. The current is proportional to the size (area) of the electrodes. The voltage is limited electrochemically to about 1.23 volts per electrode pair, or cell. These cells then can be "stacked" until the desired power level is reached.

The challenge has been to improve the economics through the use of low-cost components with acceptable life and performance. Pure hydrogen and oxygen reactants have been replaced with common fossil fuels and air, and low-cost electrodes and electrolytes have been developed.

Credit Card Center Gets "Charged" By Fuel Cell

OMAHA, NEB.-Summer heat is no stranger to this part of the country, with temperatures climbing over 100 degrees and relative humidity levels as high as 90 percent. Residents and businesses turn on every available air conditioner and fan to beat the heat, and lights may dim or go out altogether as the electrical distribution system is taxed by ever-increasing demand. Power shortages and outages this summer and last dramatize the vulnerability of the system.

While such power anomalies were a nuisance in simpler times, in today's information industry, just a few milliseconds without electricity can mean hours of headaches and millions of dollars in lost revenues for businesses.

"In the information age, electricity is more than just keeping the lights on. For businesses, it comes down to a simple mandate: Don't let the computer system go down-ever," says William Cratty, president of Sure Power Corp. of Danbury, Conn.

One of the nation's largest credit card processors, the First National Bank of Omaha, recently threw the switch on an on-site power plant that promises to make "grid glitch" a thing of the past. Fuel cells-not the electric utility's grid-are the primary power source for the bank's new Technology Center.

Four PC25 fuel cells, made by ONSI Corp. of Windsor, Conn., and related systems, developed by Sure Power Corp., were installed as part of a new "High Availability Power System". Each fuel cell generates 200 kilowatts of electricity, enough to supply electricity for nearly 150 homes, and more than 700,000 Btu per hour of usable heat.

Heat from the bank's fuel-cell installation will provide energy for space heating, increasing the overall efficiency of the bank's system to more than 80 percent. In addition, the system couples fuel cells with rotary equipment to minimize annual exposure to potential downtime.

"With millions of dollars in transactions relying on the First National Technology Center every day, the bank will only settle for the highest quality of electricity for our computer operations," said Dennis C. Hughes, director of property management for First National Bank Buildings, Inc.

The fuel cells and the power availability system offers First National computer-grade electricity and a competitive advantage. "First National can raise our customers' service expectations while generating higher revenues," Hughes said.